int main(int argc,char **argv){
        int fd = 0;
        char buf[64] = {0};
        fd = open("/dev/LED",O_RDWR);
        if(fd < 0){
                perror("open file falil!\r\n");
                return -1;
        }
        else {
                printf("open file ok\r\n");
        }
        int LED_cmd = 0;
        LED_cmd = atoi(argv[1]);
        write(fd,&LED_cmd,1);
        close(fd);
        return 0;
}